public class IdentityCardNo{
    private static IdentityCardNo instance=null;
    private String no;
    private IdentityCardNo(){

    }
    public static IdentityCardNo getInstance(){
        if (instance==null){
            System.out.println("第一次办理身份证，分配新号码！");
            instance=new IdentityCardNo();
            instance.setIdentityCardNo("No400011112222");
        }
        else{
            System.out.println("重复办理身份证，获取旧号码！");
        }
        return instance;
    }
    private void setIdentityCardNo(String no){
        this.no=no;
    }
    public String getIdentityCardNo(){
        return this.no;
    }
}